| The flow of all components of fluorine plastic centrifugal is made of fluorine plastic that can resist strong corrosion resistance, which is widely used in chemical, pharmaceutical, metallurgical and other industries for conveying corrosive media. But the design theory on the fluorine plastic centrifugal is out of date now, still stuck at the foreign technology level of that from 1970 s to 1980 s, leading to some disadvantages, such as, inefficiency, short life, low performance, poor reliability and so on. In recent years, with the development of computational fluid dynamics(CFD) technology and the application in related fields, the engineering design of centrifugal pump has come to joined the CFD study gradually. Based on the statement above, this paper put closely the fluorine plastic centrifugal pump design and computational fluid dynamics study together, starting from the study of centrifugal pump fluid flow mechanism, using numerical simulation method to study the internal flow regulation of centrifugal pump, using the simulation results to forecast the performance of the pump, thus guiding the design of fluorine plastic centrifugal pump.Aiming to the above problems, the article delivers the following studies: Firstly, on the basis of Pro/E, the original straight blade impeller was improved in a new way which was different from traditional design of centrifugal pump, with reference to the same type of metal centrifugal pump hydraulic design, and established a three-dimensional model of twisted blade impeller,at the same time, established the whole channel modeling of two different blade type impeller fluorine plastic centrifugal pump. Secondly, on the basis of the Computational Fluid Dynamics theory and the summary of the achievements of predecessors, under three working conditions, the numerical simulation of the internal flow in twisted blade impeller of fluorine plastic centrifugal pump was carried out by using FLUENT, analyzing the velocity distribution and pressure distribution, and then revealing the internal flow law regulation under different working conditions of fluorine plastic centrifugal pump. It provided reference data for the improvement of fluorine plastic centrifugal pump impeller structure. Moreover, took the multiple comparisons between the traditional cylindrical straight blade impeller of fluorine plastic centrifugal pump experimental data curve and the prediction external characteristic curve for two different blades fluorine plastic centrifugal impeller under nine different conditions perform numerical simulation of the flow field, we found the lift was higher 1m ~ 2m, the efficiency was improved by 3% to 4 %, the power also decreased a little but the overall changed little, which was well demonstrated the superiority of the improved twisted blade impeller fluorine plastic centrifugal pump. Finally, for the volute inner wall wear of the fluorine plastic centrifugal pump, a spherical cap body pits physical model was built instead of the volute inner wall roughness to perform numerical simulation of the flow field, finding that the rated condition head fell about 2.3m and under various conditions the decreased efficiency basically maintained at about 5% when the radius of the spherical cap body is 8 mm and height is 4 mm, as a result, there was a sharp falling in the performance of worn one. Therefore we verified that the roughness of the inner wall of the volute fluorine plastic centrifugal pumps had a serious impact on performance.This article provides some theoretical basis and experimental data for the fluorine plastic centrifugal pump in improving its performance, and contributes to the development and application of new products. Meanwhile, it plays an instructive role on problems encountered during the actual producing process. Besides, it also has a practical significance to reduce product costs, improve the efficiency and upgrade the quality. |
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